Refrigerating apparatus



Oct. 25, 1938.

REFRIGERATING APPARATUS Filed May 21, 1936 EvaPonn'roR' arm-v25 EWIPMMOR5m: WELLS Fla. 3.

INVENTOR v LESLIE B. M. BUCHHNHN.

WlTN ssss; FIG- E3.v

I q f wm 'w ATTORNE L. B. M. BUCHANAN 2 ,133,953

Patented Oct. 25, 1938 I UNITED STATES PATENT OFFICE narmcsm'rmemana'rns Leslie B. M. Buchanan, Springfield, Mass., assignor toWestinghouse Electric 8; Manufacturing Company, East Pittsburgh, Pa., acorporationof Pennsylvania Application May 21,1936, Serial No. smss v n10 Claims. My invention relates to refrigerating app:a|.ra--

h tus having a plurality of refrigerating elements A further object ofthe invention is to provide an improved evaporator structure wherein aportion of the same is operated to cool the ambient air and'a secondportion is effective to congeal l fluids without materially afiectingthe temperature of said ambient air.,;-

These and other objects are effected by my invention as will be apparentfrom the following specification and drawing.

20' In practicing my invention, I provide an evaporator, structuredisposed 'within the compartment of a refrigerator and including aplurality of wallmembers which define a high tempera'-' turerefrigerating element for cooling the air in 25 the compartment. Arelatively low temperature refrigerating element is disposed within saidwall members and includes provisions for congealing desserts or freezingwater.

Refrigerant is conducted. serially through the 30 low and hightemperature elements in the order.

named and means'are provided for varying the effective charge ofrefrigerant conducted thereto. \The latter means may constitute achamber for condensed refrigerant'and a displacing mem- 5 her for therefrigerant. The member normally occupies the chamber and displaces therefrigerant therein, so that the total charge of refrigerant is renderedavailable for, circulation. In this position, refrigerant substantiallyfills both the 40 low and high temperature elements, and, as the latterOperates at a relatively high temperature,

vaporization is effected therein for coolingthe air.in the food storagecompartment.

In the other position of the displacingmember;

45 a portion of the refrigerant fills thechamber so that the effectivecharge of refrigerant in the system or the chargeavailable forcirculation is reduced in an amount equivalent to the amount ofrefrigerant collected in the chamber. Accord- 50 ingly, the amount ofrefrigerant in the .evap'orator structure is reducedso that it occupiesthe low temperature element only and vaporization is @ifected therein ata relatively low temperature. The vaporized gas from the low temperatureele- 5s ment passes through the walls of the high temperatureelement,.so that some slight cooling thereof would be efiected, theamount of heat abstracted from the walls being only the semi ble heatadded to the gas as 'superheat. I Suitable means are provided forautomatically 5 varying the effective charge of refrigerant duringoperation of the system dependent upon which evaporatorrequires'refrigeration. Cooling of the air in the food compartmen to alow degree is prevented during operation of the low temperature elementso that the air therein is not dehydrated to an undesirable de- 'gree.During operation of the higher temperature element, the air in thecompartment is cooled to the desired degree without reducing itsmoisture content excessively as the element is operated at a temperaturelow enough to effect cooling but high enough to prevent a materialreduction in the dew point temperature of the air.

In'the drawing:

ing system embodying my invention; ,Fig. 2 is a sectional view of theevaporator shown in Fig. 1 and is taken along'the line 11-11 thereof;and, I I Fig. 3 illustrates d1agrammatically the connections betweenthe-high and low temperature evaporating elements.

Referring to the drawing, -1 have diagrammat ically shown a refrigeratorcabinet structure It having astorage compartment ll formed therew in forarticles-to be refrigerated. An evapora: tor structure I2 isarrangedwithin the compartment II and includes a plurality of side wallmembers l3 and I3, a rear wall I, a bottom wall l5 and a door member It.The various walls of theevaporator structure 12 define a chamber 7 lltherebetween which is preferably disposed at the top of the compartmentII and which is rendered accessible by opening the door IS. A portion ofthe walls of thestructure' H such as, for-example, the sidewalls l3 andI3, are provided with passages l8 in which condensed refrigefant isvaporized. Cooling of the air in the compartment II is effected by thewalls l3 and I3- which are in heat exchanging" relation therewith. Thewalls l3 and I3 may'be connected together by a conduit l9 providingcommunication between the bottoms of the passages i8.

Arranged within the chamber I1 is a relatively low temperaturerefrigerating element shown by way of example, as a plurality of shelves2|, 22, and, each of which may be formed with a passage 24 forrefrigerant. Trays 2! may be supcontained therein. The shelves 2 22,and-23 may be supported within the chamber H in any suitable manner as,by means of projections 26 extending inwardly from the walls I 3 and I3.In order to minimize heat leakage between the walls |3 and I3 and theshelves, the supporting pro- Jections 26 are made as small as possible,consistent with the required strength.

As the shelves 2|, 22, and 23 are shielded from the air within thecompartment II, by the various "rails of the structure l2, they areeffective when -efrigerated for cooling the fluid in the trays 25 and donot materially reduce the temperature of the air in the compartment Theshelves 2|, 22, and 23 are, preferably, connected in series for the flowof refrigerant therethrough by means of conduits 21 and 28. A conduit 29provides communication between the shelf 23 and a header 3| carried bythe wall |3. Condensed refrigerant is delivered to the lower shelf 2|!by means of a conduit 32 and vaporized refrigerant is drawn from aheader 33 provided on the wall |3 by means of a conduit 34. The shelves2|, 22, and 23 and thewalls l3 and I3'are connected for series flow ofrefrigerant therethrough in the order named, as shown in Fig. 3.

A suitable refrigerant condensing mechanism, such as, for example, amotor-driven compressor unit 35 and a condenser 36, is employed forwithdrawing vaporized refrigerant through the conduit 34 and fordelivering condensed refrigerant to a conduit 31. The motor compressorunit 35 may be of any suitable type, but I have preferred tion of arefrigerating system of the compressorcondenser-expander cycle is wellknown, it is not deemed necessary to recite in detail this operation.

A suitable float valve 4| for regulating the flow of condensedrefrigerant to the evaporator structure I2 is connected to the conduit32 and, a device .42 that operates to vary, in effect, the refrigerantcharge is disposed between the liquid conduit 21 and the float valve 4|.The device 42 includes a casing having a chamber 43 for condensedrefrigerant formed therein and a movable displacing element 44 forvarying the liquid storing capacity of the chamber 43. The element 44may be raised and lowered by a solenoid havinga core 45 and a winding46; said element 44 being raised to permit condensed refrigerant tocollect in the chamber 43 when the solenoid winding 46 is energized andbeing lowered when the winding 46 is deenergized for displacing therefrigerant in the chamber 43.

When'the element 44 is in its first, or lower position, it occupies thechamber 43 and prevents the collection of condensed refrigerant therein,and, therefore, substantially all of the refriger-' ant in the system iscirculated by the co'mpressor mechanism 35. Raising the element 44 to asecond position reduces the effective charge of refrigerant in thesystem, as condensed refrlgerant gathers in the chamber 43 and does notcirculate through the evaporator. The effective charge of refrigerantis, therefore, reduced in an v amount equivalent to the amount of liquidwhich system, so that, in the first position of the device 42, coolingof the air in the chamber II to a vposition condensed refrigerant'fillsthe passages 24 of the shelves 2|, 22 and 23 and a substantial portionof the passages I8 of the walls l3 and I3. Since the shelves 2|,.22 and23 are operated at a low temperature and are shielded from therelatively warm temperature of the air in the compartment vaporizationis effected, mainly, in

the passages l8 of the walls l3 and I3 which abstract heat from the airin the compartment The mean temperature at which the walls l3 and I3operate is determined by'the setting of a thermostat 41 and is of suchvalue that the air in the compartment is cooled to the required degreebut not low enough to effect excessive dehumidification thereof.

When the displacing member 44 is raised, the

amount of refrigerant collected in the chamber 43 reduces the chargeavailable for circulation so that condensed refrigerant is present inthe passages 24 of the shelves only. At this time the motor compressorunit 35 is controlled by a thermostat 48 which reflects the temperatureof the shelves and which is set to maintain a relatively low or freezingtemperature. vaporization is effected in the shelf passages 24 until thedesired temperature is attained at which time the thermostat 48 operatesto stop the compressor. The vaporized gas passing fromthe passages 24through the conduit 29 passes serially through the wall l3, the conduitl9 and the wall |3 to the suction conduit 34. The gas is superheatedsomewhat during its passage through the walls l3 and I3 and thereforeeffects slight cooling thereof, but the quantity of heat abstracted isrelatively small.

The electrical connections are shown in Fig. 1 and include lineconductors L1 and Lo representing the source of electrical energy. Thethermostat 41 is connected to the conductor Li and to the motor winding38, 'the opposite terminal of the winding 38 being connected to theconductor L2. A conductor 49 leads from the conductor L1 to the lowtemperature thermostat 48 and includes the solenoid winding 46. Thethermostat 48 also connects to the motor winding 33 as shown.

It will be apparent from the foregoing that the high temperaturerefrigerating element or the v 46 are closed and calling for cooling.Accordingly, the solenoid winding 46 is deenergized and the displacingelement is in its lower position wherein all of the charge ofrefrigerant is circulated. It will be understood that the control' formsno part of my invention and any other suitable method of controlling thesystem may be used. I, I have shown a different method of controlling myimproved apparatus in a copending.

application Serial No. 66,808 filed March 3, 1936, and assigned toWestinghouse Electric 8: Manufacturing Company.

Operation In the position of the apparatus shown in the Fig. 1, themotor compressor 35 is inactive due to the fact that both igiermostats41 and 48 are open. Assume now that the temperature of the lowtemperature element or shelves 2l, 22 and 23 rises above a predeterminedvalue. The ther- 5 mostat 48 closes and energizes the circuit includingthe conductor 49, the winding 46 of the device 42 and the motor winding38. The compressor unit 35 now operates to circulate refrigerant as iswell understood and the displacing elein ment 44 is raised so that thecharge of refrig-T erant available for circulation is reduced.Accordingly, the shelf passages 24 only receive condensed refrigerant asan insufllcient amount is passed thereto to cause refrigerant to pass 15through the conduit 29 and spill into the wall l3.

It will be understood that any condensed refrigerant present in thewalls l3 and H3 at the time that the compressor starts will be vaporizedbut this is soon exhausted after which vaporization continues only inthe passages .24 of the shelves. Operation continues until thetemperature is reduced to a relatively low degree at which time thethermostat 48 is opened, and thesolenold winding 46 and the motorwinding 38 are deeng5 ergized. Accordingly, the motor compressor 35stops and the displacing device 44 drops. Therefrigerant containedin thechamber 43 is displaced and drains back to the condenser 38 throughconduit 31 although a small portion may 80 pass to the float valve 4I.Preferably, the conduit 31 connects tothe chamber 43 at "a level lowerthan the connection to the float 4! so that the major portion (of thedisplaced refrigerant drains through conduit 31. as Assume that the walltemperature now rises to the value at which thethermostat 41 is set. IThe latter operates to close its'contacts and energizes the motorwinding 38, without energizing the solenoid winding 46. Refrigerant iscirculat- 4 ed by the motor-compressor, 35 and, as the full charge isavailable for circulation, the passages 24 and 18 are occupied bycondensed refrigerant.-

Refrigerant contained within the passage 18 is vaporized by the heat ofthe walls 13 and I3",

45 which heat is abstracted from the air within the compartment ll. Asthe shelves 2!, 22and 23 are at a relatively low. temperatureand areshielded from the air in the compartment I I, substantially novaporization is efiected therein. Refrig- 50 eration continues aslong'as the compressor unit 35 operates and, when the temperature of theair in the compartment ll or the temperature of the walls l3 and I3 isdepressed to the desired value, the thermostat 41 opens and terminates55 operation.

It will be understood that, during this operation, the refrigerant inthe walls i3and I3 and in the shelves 2l,,22 and 23 will attain the sametemperature as it is subjected to substantially the 0 same pressurethroughout. The temperature at which the thermostat 41 operates toterminate operation of the compressor 35 is lowerthan the temperature atwhich the thermostat 48 operates to initiate operation of the same. Thisis de- 5 sirable in order that the compressor 35 is not maintained inoperation by the thermostat 48 each time the thermostat 41 operatestoterminateoperation of the same, which condition would exist if thecircuit closing temperature of 70 the thermostat 48 were below thecircuit opening temperature of the thermostat 41. Therefore, the mean oraverage. temperatureat which the walls l3 and 13' are operated is higherthan themean or average temperature of the shelves. 15 Withthethermostat 48 set to close at a higher ture of the-air when operating.

temperature than the opening temperature of;-

the thermostat 41, evappration is effected in the shelves when the wallsare refrigerated, although in a small amount. It might appear from the.foregoing that, where the difference between the. 5 closing temperatureof the low temperature thermostat 48 and the opening temperature ofhigher temperature thermostat 41 is small, .operation of the compressor35 would be initiated by the low temperature thermostat 48.- shortly 10after termination of its operation-by the high temperature thermostat41. This is not the case as the low temperature shelves are shieldedfrom the air in the compartment II and are subjected to the coolingeffect of the stored ice in the trays 5 I so'th'at a relatively longperiod of time will usually elapse before the shelves are increased intemperature to the value at which the thermostat 48 closes.

If the low temperature thermostat 48 is closed 20 for refrigerating thelow temperature shelves 2|, 22 and23 and the thermostat 41 closes, itwill be seen that the solenoid coil 48 will be shunted thereby and willbe, deenergized. Accordingly, the member 44 dropsand the supply ofinactive 5 refrigerant in the chamber 43 is displaced and passed to theevaporator structure. The increase in the supply results in condensedrefrigerant passing upwardly in the conduit 23 and spilling over intothe walls l3, the conduit l8 and the wall l3, so that refrigeration ofthe walls l3 and I3 is effected. If the thermostat 41 then opens and thethermostat 48 remains closed, operation of the compressor unitcontiniies and the coil 46 of the solenoid is again energized forraising 3 the member 44. Refrigerant then collects in the chamber 43 andreduces the charge, in effect, so that refrigeration is effected only inthe shelf passages 24. K i

With this system of control, it will be seen that the high temperatureevaporating elements are given preference over the low temperatureelements, but other suitable arrangements'of the control apparatus maybe employed.

In my copending application, Serial No. 15,003, 4

and broadly claim arefrigerating system having l iigh and lowtemperature evaporatingelements .and employing a device for varying theeffective 50 charge of refrigerant delivered thereto wherebyrefrigeration is selectively obtained in either, element. From theforegoing, it'will be apparent that I have provided an improved systerhof this I kind'wherein the high and low tempera ments are disposed in asingle compartment and 1 in which the low temperature element is soshielded from the air in the compartment that it effects substantiallyno reduction in tempera-- .80 While I have shown my invention in but oneform, it will be obvious to those skilled in the art that it is not solimited, but is susceptible,- of various changes and modificationswithout departing from the spirit thereof, and I desire, 06' therefore,that only such limitations shall be ure eleexposed to the air within thecompartment and having a passage for refrigerant formed therein, saidstructure including a relatively low temperature refrigerating elementdisposed withinsaid high temperature element for receiving substances tobe congealed and having a second passage for refrigerant formed therein,means for conveying condensed refrigerant to the evaporator structure,and means for selectively adjusting the flow ofrefrigerant conveyed bythe lastnamed means to said passages wherein it is vaporized toprimarily effect refrigeration of either the high or low temperaturerefrigerating elements.

2. In refrigerating apparatus, the combination of a cabinet structurehaving a compartment formed therein, an evaporator structure arrangedwithin the compartment and including a plurality of wall members exposedto the air within the compartment, said wall members having a passagetherein for refrigerant, said evaporator structure including a shelfdisposed within the wall members and having a passage therein forrefrigerant, means for conveying condensed re- 'frigerant to theevaporator structure and means for selectively controlling the flow ofcondensed refrigerant to said passages wherein it is vapor ized toprimarily effect refrigeration either of the wall members or of theshelf.

3. In refrigerating apparatus, the combination of a cabinet structurehaving a compartment formed therein, an evaporator structure disposedwithin said compartment and including wall members for cooling the airin the compartment and constituting a high temperature refrigeratingelement, said evaporator structure including a shelf disposed within thewall members and constituting a low temperature refrigerating element,means for condensing refrigerant vapor and for translating it to saidrefrigerating elements, and means for controlling the flow ofrefrigerant translated by the last-named means so that it is effectivefor. refrigerating primarily, ei-' ther the low or high temperatureevaporating elements. 1

4. In a refrigerating system, the combination of a cabinet having acompartment formed therein, an evaporator structure disposed within 7the compartment and including a plurality of wall members defining achamber therebetween,

' at least a portion of. said wall members including a passage forrefrigerant, a shelf arranged within the chamber and having a passagetherein for refrigerant, means for circulating refrigerant in seriesthrough the passages of the shelf and wall member in the order named andmeans for selectively varying'the flow of refrigerant transing a shelfmember disposed within the wall members and defining a low temperatureevapoiating element, a refrigerating machine for condensing refrigerantvaporized in said evaporating elements and for translating it in seriesthrough said 10W and high temperature evaporating elements, and a devicefor varying the effective charge of 7 refrigerant translated by therefrigerating machine and movable to a first position wherein condensedrefrigerant occupies the low and high temperature evaporating elements,said device being adjustable to a second position in which condensedrefrigerant occupies the low temperature evaporating element only.

6. In refrigeration apparatus, the combination of a cabinet structurehaving a cooling compartment therein, a relatively high temperatureevaporating element arranged in heat exchanging r'elationwith the air inthe compartment and including wall members for defining a chambertherebetween, a relatively low temperature evaporating element arrangedwithin said chamber for chilling substances to be congealed, arefrigerating machine for conveying condensed refrigerant to said lowtemperature element, means connecting said low and high temperatureelements and providing for series flow of refrigerant therebetween, anda device for varying the effective charge of refrigerant in therefrigerating ma chine and operative, in a first position, to delivercondensed refrigerant to the high and low temperature evaporatingelements, said device being adjustable to a second position inwhichcondensed refrigerant is delivered to said low temperatureevaporating element only.

7. In refrigeration apparatus,'the combination of a cabinet structurehaving a cooling compartment therein, a relatively high temperatureevaporating element arranged in heat exchanging relation with the air inthe compartment and including wall members for defining a chambertherebetween, a relatively low temperature evaporating element arrangedwithin said chamber for chilling substances to be congealed, arefrigerating machine .for conveying condensed rehfrigerant to said lowtemperature element, means connecting said low and high temperatureelements and providing .for series flow of refrigerant therebetween, anda device for varying the effective charge of refrigerant in therefrigerating machine and operative, in a first position, to

deliver condensed refrigerant to the high and low temperatureevaporatingelements, said device being adjustable to' a second position in whichcondensed refrigerant is delivered to said low temperature evaporatingelement only, means for initiating operation of the refrigeratingmachine and for effecting movement of the device to its second position,said last-mentioned means effecting movement of the device to its firstposition, when terminating operation of the refrigerating machine andmeans for initiating and terminating operation of the refrigeratingmachine without effecting movement of said device.

8.' In refrigerating apparatus, the combination of a cabinet structurehaving a compartment therein, a relatively high temperaturerefrigerating element disposed in said compartment for cooling the airtherein,- a relatively low temperature refrigerating element disposedwithin said higher temperature element, means for condensing therefrigerant vaporized in said refrigerating elements, means forconveying refrigerant from the condensing means'to said elements in suchmanner that liquid refrigerant flows into the low temperature element inpreference to the higher temperature element, and means for selectivelyvarying the amount of refrigerant in perature element for effectingrefrigeration thereof at relatively high temperature and pressure, andat another time, the high temperature element receives substantially noliquid refrigerant so that vaporization at relatively low temperatureand pressure is eflfected in the low temperature element and means forselectively producing the effect of increasing the refrigerant charge tothe extent of causing liquid refrigerant to fill a substantial portionof the higher temperature element, for effecting refrigeration atrelatively high pressure and temperature in the higher temperatureelement or producing the effect of decreasing the refrigerant charge tothe extent that the higher temperature element receives substantially noliquid refrigerant, for effecting refrigeration at low pressure andtemperature in the low temperature element.

9. In refrigerating apparatus, the combination of a zone toberefrigerated, a relatively high temperature evaporating elementdisposed for cooling the air in said zone and forming a cooling chamberwithin the zone, a relatively low temperature element for cooling mediain the chamber to a relatively low temperature said low temperatureelement being shielded by the high temperature element from the airwithin said zone, and means for supplying condensed refrigerant to saidelements and adjustable to a first position wherein condensedrefrigerant-substantially fills the low temperature element and aportion of the high temperature element, said means being adjustable toa second position wherein condensed refrigerant is delivered to the lowtemperature element only.

10. In refrigerating apparatus, the combination of means defining a zoneto be refrigerated at a relatively high temperature, an evaporatingelement disposed for cooling the air in said zone and defining a chambertherein, a second evaporator element disposed within said chamber andshielded by the first evaporating element from the air in the zone forrefrigerating media in the chamber to a relatively low temperature andmeans for translating refrigerant in series first through the secondelement and thence through the first element.

LESLIE B. M. BUCHANAN.

I CERTIFICATE OF CORRECTION. -,Pa,te'nt No. 2,1 ,955. October 25,- 19

LESL'IE B. M. BUCHANKNL. i It is hereby certified that error appearsfinvthe printed specification of the above numbered patent requiringcorrection as follows: Page 5, first --col1m 1n, line claim 8, beginningwith the words "and means for" strike out all to and. including the word"element", in-line 1 6, same claim and that the said Letters Patentshould be read with this eerreetien therein that the. same may conformto the record of the casein: the Patent Office.

'Signed and sealed this th'day of December, A. D. 1958.

Henry Van Arsdale (Seal) Acting vCommissaioner of Patents.

